Documentation: Document Maintainer Widget

I left feedback in the MR.

Rebasing brought 7.x-3.x as the MR was initially created against it... I reverted that and everything is up to date now.
RTBC.

fjgarlin → closed merge request !315

fjgarlin → changed the visibility of the branch 1.0.x to hidden.

fjgarlin → closed merge request !312

Due to the rebasing issues, I needed to create a new MR with the same code but a clean git history.

Merged now.

Automatically closed - issue fixed for 2 weeks with no activity.